Figure 28.- -The Bell Telephone transducer, frequency 200 

 cj).s. to 10,000 C.P.S. 



SUMMARY AND CONCLUSIONS 



1. Guiding fishes by means of sound gen- 

 erating equipment installed at dams and diver- 

 sions would be desirable because of its free- 

 dom from physical floating equipment and 

 ease of maintenance. 



2. Fishes have been conditioned to respond 

 to sound as a signal for food, but the evidence 

 of attraction to sound alone is rare and ques- 

 tionable. 



3. Certain fishes may be frightened mo- 

 mentarily by any noise but adjust to disregard 

 it (become conditioned) almost instantaneously. 



4. The four sound propagating pieces of 

 equipment tested at Leetown, West Virginia, 

 are described as follows: 



a. "Water hammer"- -electromagnetic 

 transducer producing sine curve sound ranging 

 from 67 to 3,000 c.p.s. 



b. Piezo-electric type crystal trans- 

 ducer producing sine curve sound ranging 

 from 12,000 to 70,000 c.p.s. 



c. "Wampus"- -hydraulic (underwater) 

 turbine noisemaker, sound frequency audible, 

 disclosure of frequency characteristics not 

 permitted, but of low frequency. (U.S. Navy 

 classified equipnnent) 



d. Electromagnetic sound projector, 200 

 to 10,000 c.p.s. sine curve sound. Bell Tele- 

 phone IK- 2. 



5. The hatchery pond in which the tests 

 were conducted was approximately 60 feet 

 wide and 450 feet long. The bottom and sides 

 were of marl mud, a carbonate which absorbs 

 sound waves very well. 



6. In the tests rainbow trout 4 to 1 2 inches 

 long were used, as well as a few 14 to 24 

 inches in length, and several hundred brown 

 trout approximately 1 l/2 inches long. Turtles, 

 frogs, toads, molluscs, and aquatic insects 

 were kept in live boxes. 



7. In order to measure the reaction of the 

 fish to the various sound waves a special 

 structure was built in the pond. This structure 

 was 100 feet long, 3 feet wide, and 3 feet deep, 

 divided into 10 sections by sliding gates. 



8. A typical test was as follows: One 

 hundred fish were placed in each section 

 (total 1,000). The transducer (previously ad- 

 justed to a given frequency), located at one 

 end of the structure, was turned on simul- 

 taneously with the lifting of all gates. After a 

 given length of time the gates were lowered 

 and the sound turned off. The fish in each 

 compartment were then counted to determine 

 their distribution in the structure. From this 

 (and from observations made during the test) 

 the reactions of the fish to a given sound 

 could be determined. 



9. After the initial "start" the fish showed 

 no response to continued sound waves of low 

 frequency, 



10. There appeared to be no response, either 

 initial or otherwise, to the high frequency 

 sovinds. 



11. The wampus or underwater turbine pro- 

 duced a sound intensity great enough to burst 

 one's eardrunas if he should put his head under 



29 



